Pool covers for in-ground pools are attached by taut straps at the periphery of the cover which are attached to anchors in the decking around the pool. The flexible cover is to lay taut over the edge of the pool roughly in a plane parallel to the water surface.
Unfortunately, obstructions which extend vertically over the level of the pool edge often interfere with the pool cover. These may be poles or columns supporting canopies or roofs close to the edge of the pool; other obstructions such as a handrail adjacent steps leading to the pool bottom may actually extend into the pool water region.
In these areas, the pool cover must be split to permit the cover to go around the obstacle so that it can again lay horizontally at the level of the decking or pool edge. The split area must be again attached to maintain the integrity of the pool cover.
Currently, a series of straps and buckles are used to re-join the edges of the split regions of the pool cover. These straps and buckles add weight to the pool cover in localized areas making installation and removal more cumbersome. They also aesthetically detract from an otherwise streamlined appearance. Extra personnel are sometimes required to handle the cover in the obstacle areas and also to detach and re-attach straps which are rather labor intensive.
The prior art shows the use of zippers attached to pool covers. U.S. Pat. No. 4,109,325 of Shuff describes an inflatable pool cover with integral weighted skirts which are usually submerged. By introducing pressurized air under the pool cover, it can be made to rise above the edge of the pool.
U.S. Pat. No. 5,621,926 of La Madeleine describes a swimming pool cover system wherein the pool cover is attached to the periphery of the pool, but the center is raised by a cable on a boom to form a type of tent canopy over the pool.
In both of these patents of Shuff '325 and La Madeleine '926, zippers in the pool cover are used to permit a sealable opening to admit swimmers to use the pool with the pool cover attached, to take advantage of the space provided between the pool surface and the pool cover.
U.S. Pat. No. 5,722,098 of Stern describes a pool cover with drainage and filter means, wherein the filter and drain region is attached to the central region of a pool cover by some mechanism, among which is a zipper.
U.S. Pat. No. 6,691,334 of St-Hilaire describes a swimming pool covering structure in two parts. In St-Hilaire '334, the zipper is an integral part of the actual covering of the pool. A flexible central section extends over the water area of the pool. A flexible anchoring section is attached to the edge of an above-ground pool or to the deck surface around an in-ground pool much like a frame. The central section is then attached to the anchoring section using a long zipper extending all the way around the edge of the pool.
None of the cited prior art patents make use of one or more sliding zipper elements to permit a pool cover to be fitted around vertical obstacles over the water or deck areas. None of the cited patents uses a zipper to make a certain part of the covered areas removable to gain access to an adjacent feature, such as a spa area.
Also, the prior art does not relate to safety pool covers which must comply with ASTM specifications.